An image forming apparatus such as an electrophotographic color printer includes photosensitive members which correspond to four colors (black, yellow, magenta, and cyan), respectively.
There has been known an image forming apparatus in which a charging device, a cleaning device, and the like are provided around each photosensitive member, and electric power is supplied to the charging device, the cleaning device and the like from a body of the image forming apparatus.
Further, an image forming apparatus includes four drum units having photosensitive drums corresponding to respective colors. Each of the drum units includes a developing roller electrode, a wire electrode, a grid electrode, and a cleaning electrode. The main body casing of the image forming apparatus includes contacts corresponding to the respective electrodes. When the drum units are mounted in the main body casing, the electrodes come into contact with the contacts, respectively.
In this image forming apparatus, each of the drum units includes a developing roller electrode, a wire electrode, a grid electrode, and a cleaning electrode.
Therefore, the main body casing is required to have the number of contacts corresponding to the respective electrodes, so that it is difficult to simplify the structure of the main body casing.